Lactone adducts



LACTONE ADDUCTS Thomas F. Carruthers, South Charleston,

to Union Carbide Corporation, York No Drawing. Application April 27, 1956: Serial No. 581,011

20 Claims. (Cl. 260-405) W. Va., assignor a corporation of New This invention relates to lactone adducts that are useful as plasticizers in vinyl and other resins, and to a method of preparing such esters.

A number of plasticizers for vinyl resins, cellulose derivatives, and the like, have been known for some time, di(2-ethylhexyl) phthalate being among the relatively non-volatile esters of simple molecular structure known for this purpose. While esters of this type possess a number of important advantages as resin plasticizers, the combinations of resin and plasticizer leave something to be desired in so far as permanence is concerned, since gradual loss of plasticizer occurs by evaporation or by extraction with liquids which may come into contact with the plasticized resin. Thus, for example, shower curtains of plasticized resin tend to lose plasticizer by water extraction. Furthermore, the simple ester plasticizers are active solvents for many substances and tend to migrate from the plasticized article to other materials which come into contact with it.

In accordance with the preferred embodiment of the invention, lactones are reacted with hydroxy acid esters to form adducts having one or more terminal hydroxy groups that are eminently suitable as plasticizers in various resins, e.g., copolymers of vinyl chloride and vinyl acetate, natural rubber, GRS rubber, copolymers of acrylonitrile with ethylenically unsaturated compounds such as butadiene, polyvinyl butyral and polyvinyl chloride, nitrocellulose and the like. These adducts can, if desired, be acylated to insolubilize the terminal hydro'xyi groups and thus further improve their resistance to extraction by water from resins with which they are combined.

The lactone used as a starting material may be any lactone, or combination of lactones, having at least six carbon atoms in the ring and represented by the general formula:

in which n is at least four, at least n+2 R's are hydrogen, and the remaining Rs are substituents selected from the group consisting of hydrogen, alkyl, cycloalkyl, alkoxy and single ring aromatic hydrocarbon radicals. Lactones having greater numbers of substituents other than hydrogen on the ring, and lactones having five or less carbon atoms in the ring, are considered unsuitable for the purposes of the invention because of the tendency that polymers thereof have to revert to the monomer, particularly at elevated temperature.

The lactones preferred in this invention are the epsiloncaprolactones having the general formula:

wherein at least six of the Rs are hydrogen and the-remainder are hydrogen, alkyl, cycloalkyl, alkoxy or single ring aromatic hydrocarbon radicals, none of thesubstituents contain-more than about twelve carbon atoms, and the total number of carbon atoms in the substituents on a lactone ring does not exceed about twelve. Unsubstituted epsilon-caprolactone, in which'tall the Rs are hydrogen, is derived from 6-hydroxy-hexanoic acid. Substituted epsilon-caprolactones, and mixtures thereof, are available by reacting a corresponding substituted cyclohexanone with an oxidizing-agent such as peracetic acid, as described in copending application. Serial No. 548,754, filed November 23, 1955. The cyclohexano'nes maybe obtained from substituted phenols. or by other convenient synthetic routes.

Among the substituted epsilon-caprolactones considered most suitable for the purposes of the invention are the various monoalkyl epsilon-caprolactones such as the monomethyl-, monoethyl-, monopropyl-, mono'isopropyl-, etc. to monododecyl epsilon-caprolactones; dialkyl ,epsilon-caprolacto'nes in which the two alkyl groups are substituted on the same or different carbon atoms, but not both on the epsilon carbon atom; trialkyl epsilon-caprolactones in which two or three carbon atoms of the lactone are substituted, so long as the epsilon carbon atom is not disubstituted; alkoxyepsilon-caprolactones such as methoxy, and ethoxy'epsilonrcaprolactones; and cycloalkyl, aryl, and aralkyl epsilon-caprolactones such as cyclohexyl, phenyl and benzyl epsilon-caprolactones Lactones having more than six carbon atoms in the ring, e'.g., zeta=enantholactone and eta-caprylolactone may also be reacted in accordance 'with the method of the invention.

The hydroxy-acid-esters that are suitable for reaction with the lactone or mixture of lactones in the method of the invention typically include:

the Z-ethylhexyl ricinoleate,

3-methyl-l,5-pentanediol diricinoleate,

glyceryl ricinoleateor castor oil,

tributyl citrate.

It is believed that the hydroxy] groups open and add on lactone rings to form ester groups having new terminal hydroxyl groups, as represented for example by the equation: a

s a ,3 R'0H+R 1E cR1 ).C=O n'oC(QRyMgH OI;.

in which R stands for a hydroityester-residue, and that i any of the new-terminal hydroxyl groups are in turn capable of opening and adding on one or more lactone rings:

The adducts obtainable by reactingone or more lactones with a hydroxy, ester in accordance with the invention may therefore be conveniently represented by the in which n is at least four, at least n+2 R's are hydrogen, the remaining R's are substituents selected from the group consising of hydrogen, alkyl, cycloalkyl, alltoxy and single ring aromatic hydrocarbon radicals, and the total number of carbon atoms in the substituents on a given group does not exceed about twelve; R is a residue of a hydroxy' acid ester; x'is an average of at least one; and y corresponds to the number of hydroxyl groups on the initial hydroxy ester and is at least one.

Generally, it is desirable that the molar proportions of the lactone and the hydroxy'ester reactants be related approximately to the number of hydroxyl groups. When using a glyceride containing three hyrdoxyl groups, for example, the molar ratio of lactone to glyceride should be at least about 3:1 and preferably somewhat higher,

unless special efiects are desired. The average molecular weight of the adducts may be controlled. as will readily be' understood by those skilled in the art. by selection of the particular starting materials as well as by adjustment of the molar ratio of the lactone to the ester. Thus, for example, molar ratios of lactone in excess of the amount equivalent to the number of hydroxyl groups will result in higher molecular weight adducts having chains each containing several lactone residues. 1 1 g I The reaction is carried out by heating the mixed retion may conveniently be represented by the general formula R'(OL,,Y)

in which Y is H or acyl and the remaining symbols are as indicated previously.

The concentration of a lactone adduct of the invention as a plasticizer in a resin may vary widely, depending upon the particular results desired. Low concentrations, e.g., as low as about 5% by weight, are employed as processing aids in rigid compositions rather than for plasticizing action. Higher concentrations up to about 50% or even more are used when flexibility is the overriding desideratum.

The method of the invention and the utility of the products obtained thereby will become further apparent from the following detailed examples included to illustrate the best modes presently contemplated for carrying out the invention. In these examples, the acidity is reported in terms of the number of cc. of normal base required to neutralize one'grarn of ester and the hydroxyl .value is reported in terms of percent OH as determined bya modification of the acetic anhydride-pyridine method, similar to that described in Ind. Eng. Chem. Anal. Ed., vol. 17, pages 394-97. The course of the reaction between the lactone or lactones and initiator was followed, in the examples, by observing the refractive index and the reaction was assumed to be complete when the index had reached a maximum.

Example 1 (theory-l390),.a saponification equivalent of 198.2 (theactants to a temperature between about 100 and 250 C.

for a time sufficient to complete the reaction, as readily indicated by the refractive index, whichreachcs a maximum when the reaction is complete. If desired, the reaction may be accelerated and carried out at somewhat lower temperatures by admixing with the reactants a minor proportion, e.g., as little as 0.1 up to about 2% by weight of the total charge, of catalyst. Suitable catalysts include organic acids such as acetic acid, propionic acid, Z-ethylhexanoic acid, and the like, mineral acids. bases such as sodium methylate, the various ester interchange catalysts, and organic metal compounds including particularly organic tin oxides, titanates, chelates and acylates. After completion of the reaction, low boiling materials may be stripped from the adduct by heating it at reduced pressure.

The lactone adducts thus formed are excellent plasticizers and are compatible as such in vinyl and other resins and elastomers. In order, however, to make them more miscible with vinyl chloride resins, for example, and to reduce their loss from such resins by water extraction, the adducts are preferably acylated by reacting, at elevated temperature, the terminal hydroxyl groups. with excess acylating agent. Anhydrides such as acetic anhydride and propionic anhydride are preferred over acids because of their ability to react at lower temperatures and their consequently lesser tendency to favor decomposition of the polyester or other side reactions such as ester rearrangement. After completionof the acylation, low boiling materials may again be stripped from the acylated adduct by heating it at reduced pressure.

ory 198.5), a hydroxyl value of 3.08% and an index of refraction atn 30/D of 1.4739.

The free hydroxyl groups of the epsilon-caprolactonecastor oil polyester were acetylated by heating for four hours at 1l0125 C. with a excess of acetic anhydride. 'All low boiling materials were then stripped off in a goose-neck still to 185 C. at 4 mm. The acetylated product was a viscous liquid having an acidity of 0.0211 cc. N base/g, a saponification equivalent of 153.7 (theory 151.6) and a refractive index at n 30/D of 1.4668.

Example 2 Four mols of epsilon-caprolactone (456 grams), onethird mol of-castor oil (311 grams) and 7.7 cc. of 2- ethylhexanoic acid (1% of charge) were stirred and heated at 140-l99 C. until the refractive index had reached a maximum. This required 7.5 hours. The reaction product was a waxy solid having an acidity of 0.125 cc. N base/g., a saponification equivalent of 156.3 (theory 153.5), and a hydroxyl value of 2.05% (theory 2.12%

The adduct thus obtained was acetylated by heating for four hours at 110135 C. with a 50% excess of acetic anhydride. All low boiling materials were then stripped off in a goose-neck still to 197 C. at 3 mm. The acetylated product was a soft wax having an acidity of 0.058 cc. N base/g, and a saponification equivalent of i3? (theory 135).

Example 3 329 grams (0.8 mol) of 2-ethylhexyl ricinoleate, pre' 1' pared as described in US. Patent 2,310,395 to Thomas F.

aciduntil the refractive index 'had' reached a maximum.

The ;nonacylated and acylatedadducts obtained; in

accordance with the preferred embodiment of, theinvene Thishrequircd 2.5 hours at 123-202 C. The productwas. aviscous liquid having an acidity of 0.146 cc: N.

base/g, a hydroxyl value of3'.6%' (theory 3.24) and a saponification equivalent of 261.5 (theory 262.4).

400 grams of the Z-ethylhexyl ricinoleate-caprolactone adduct thus obtained were acetylated by heating for four hours at 100 C. with a 50% excess of acetic anhydride and then stripped in a goose-neck still to 177 C. at 4 mm. Hg. 492 grams of the product were obtained. It has an acidity of 0.0336 cc. N base/g., a viscosity of 52 cp. at 25 C. and a saponification equivalent of 191.1 (theory 188.9).

This polyester proved to be compatible with an 85% vinyl chloride-15% vinyl acetate copolymer VYHH and with nitrocellulose, as well as-with 97% vinyl chloride- 3% vinyl acetate copolymer VYNW, as demonstrated later herein.

Example 4 0.8 mols of a mixture of beta-, gammaand deltamethyl-epsilon-caprolactones (102 grams), 0.8 mols of tri-butyl citrate (288 grams) and 1% of acetic acid as catalyst were heated and stirred together until the refractive index ceased to rise. This required 3 /3 hours at 125-172" C. The reaction mixture was stripped in a goose-neck still to 150 C. at 6 mm. to leave 390 grams of residue product. The adduct was a liquid having an acidity of 0.260 cc. N base/g, an index of refraction at n 30/D of 1.4500, a viscosity of 110 cps. at 25 C., a saponification equivalent of 126.4 (theory 122.1) and a molecular weight of 465 (theory 488).

The adduct thus obtained was acetylated by heating for four hours at 126 C. with a 50% excess of acetic anhydride, then stripped in a goose-neck still to 178 C. at 4 mm. The acetylated adduct was a liquid having an acidity of 0.150 cc. N base/g, a viscosity of 103 cps. at 25 C. and a saponification equivalent of 107.4 (theory 106.1).

Example 5 One mol of epsilon-caprolactone (114 grams),--one' third mol of castor oil (311 grams) and five grams of acetic acid (1.15%) were heated an stirred together until the refractive index had reached a maximum. This required 4 /2 hours at l62-170.C. 425 grams of adduct were obtained. It was a viscous liquid having an acidity of 0.125 cc. N base/g, an index of refraction at n 30/D of 1.4747, a saponification equivalent of 212.2 (theory 212.6) and a hydroxyl value of 3.6% (theory 4.0%).

375 grams of the adduct thus obtained were acetylated by heating with 153 grams (50% excess) of acetic anhydride for four hours at 1l5-l35 C., then stripping in a goose-neck still to 160 C. at 3 mm. The acetylated adduct was a liquid having an index of refraction atn 30/D of 1.4682, an acidity of 0.0448 cc. N base/g, a saponification equivalent of 160.2 (theory 155.8) and ,nil hydroxyl value.

Example 6 Two mols of epsilon-caprolactone (228 grams) and one-third mol castor oil (311 grams) were heated and stirred together without a catalyst until the refractive index reached a maximum. This required four hours at 185-220 C. The adduct was a viscous liquid that had an acidity of 0.058 cc. N base/g., a hydroxyl value of 2.9% (theory 3.15%) and a saponification equivalent of 179.3 (theory 179.8).

300 grams of this adduct were mixed with 100 grams (50% excess) of propionic anhydride and heated for four hours at 120-435 C. The reaction mixture was stripped in a goose-neck still to yield 327 grams ofresidue product. The acylated adduct was a viscous liquid having an acidity of 0.032 cc. N base/g. and a saponification equivalent of 149.5 (theory 148.9).

Example 7 3-methy1-1,5-pentanediol diricinoleate was prepared by refluxing one mol .of 3.-methyl-1,5.-pentanediol and two mols-of ricinoleic acid in toluene and removing-the water formed by means-1 of a decanter. plate in twenty-three hours at 132-181 'C. The hydroxy ester was recovered as a residue by stripping in a gooseneck still to 191C. at 3 mm. It was a'viscous liquid having an acidity of 0.161 cc. N base/g., a saponification equivalent of 347.7 (theory 339.5) and a hydroxyl value of 4.2% (theory 5.0%).

One-third mol of the ester so prepared (225' grams), one mol of methyl-epsilon-caprolactone and 1.7 grams of acetic acid (0.5%) were heated and. stirred until the refractive index had reached a maximum. This required six hours at 147-154". C.. The reaction mixture .was

' stripped in a goose-neck still to yield 353 grams of residue C. at 3 mm.

product. The adduct was a liquid having an acidity of 0.125 cc. N base/g., a saponification equivalent of 212.6 (theory 212.7) and a hydroxyl value of 2.7% (theory 3.2%).

300 grams of this adduct were reacted with 93 grams (50% excess) of propionic anhydride for three hours at 115134 C., then strippedin a goose-neck still to 185 321 grams of residue product were obtained. The acylated adduct was a viscous liquid having an acidity of 0.050 cc. N base/g., a saponification equivalent of 176.5 (theory 173.1) and an index of refraction atn 30/D of 1.4670. 1

Example 8 One mol of epsilon-caprolactone (114 grams), one mol of methyl-epsilon-caprolactone (128 grams), one-third mol of hydrogenated castor oil, a glyceryl tri-l2-hydroxy stearate also nown as Castorwax (313 grams), and 3 cc. of acetic acid were heated and stirred together until the refractive index had reached a maximum. This required six hours at 188204 C. After pot stripping to 200 C. at 3 mm., 546 grams of a residue product were obtained. The adduct had a hydroxyl value of 2.7% and an acidity of 0.054 cc. N base/g.

502 grams of the adduct so prepared were mixed with grams (50% excess) of acetic anhydride and heated for four hours at l02-125 C. The reaction mixture was stripped to 180 C. at 5 mm. to yield 532 grams of residue product. The acetylated adduct had an acidity of 0.0213 cc. N base/g, nil hydroxyl value and a viscosity of 910 cps. at 25 C. j

The acylated adducts of the various examples were all found to be compatible with and have a fiexibilizing effect on vinyl chloride-vinyl acetate copolymers. Samples of a 97% vinyl chloride-3% vinyl acetate copolymer VYNW, plasticized with the acylated adducts of Examples 1 to 8, were tested tocompare them with dioctyl(di-2-ethylhexyl) phthalate, a well-known and successful commercial plasticizer, and to evaluate their pertinent characteristics. In the table immediately following, effectiveness is the concentration of plasticizer based on the total weight of resin plus plasticizer producing an elastomer having an elongation of 100% at 25 C. under a load of 1000 p.s.i. (applied at a constant rate in 74 seconds); the elongation is the increase in length at rupture with the sample at 25 C.; flex temperature (T and (T are indicative of pliability and are points corresponding to a stiffness modulus of 135,000 p.s.i. and 10,000 p.s.i., respectively, on a temperature-stiflness curve, the stiffness measurements being determined on a Clash and Berg Torsional Stiffness Tester as outlined in ASTM Method D1043-51 (Ind. Eng. Chem. 34, 1218, 1942); the brittle temperature is a measure of flexibility at low temperature and is determined by an impact test as defined in ASTM Method D746-52T; the percent Water and oil extraction is the percentage weight loss of four mil films immersed in distilled water and in refined mineral oil, respectively, for a period of ten days at 25 C.; the durometer fVAf' hardness is a measure of resistance to indentation of an 0.25 inch specimen by a pin equippedv with a truncated Reaction was com '-the SP1 volatility in the percent weight loss of four to six mil films after contact with activated carbon granules for twentyfour hours at 70 C., as described in ASTM 8 This embodimentof the invention is further illustrated by the following example:

- I Q Example 9 Two mols of epsilon-caprolactone (228 grams), one

Method D1203-52T; the heat stability is a measure of the time in minutes required to reduce the blue light mol of ricinoleic acid (298 grams) and 5 cc. of acetic reflectance to 15% at 158 C.; and the sweat-out is a acid (1%) were heated and stirred together until the measure of exudation of the plasticizer on aging at room refractive index had reached a maximum. This required temperature. The values below effectiveness in the five hours at i48-154 C. After stripping in a goosetable are based on resin containing the efiective percentneck still to 155 C. at 2.5 mm., 516 grams of a residue age of plasticizer: product remained. The adduct was a liquid having 21 Example No 1 2 3 4 5 6 7 8 Dioctyl Phthalate Effectiveness. percent in VYNW 43.3 40.5 38.5 40.4 42 41.0 43.4 30.7 38.5 Tensile Strength,p.s.l- 2.200 2. 310 2.230 2.270 2,175 2.3m 2.190 2.11 0 2.470 Elongati n. perrent 365 355 360 340 325 360 300 360 385 ASTM Stiffness Modulus. p.51 580 670 970 75 475 700 850 550 760 Flex-temperature (Ty), C..- 44 23 -45 25 34 -29 35 -28 -36 (Tn 0 -11 -1 -9 -4 -1 5 -s -4 Brittle Temperature. C 38 33 -51 27 40 33 41 37 -34 Percent Extraction: 011 20.2 11.7 23.0 15.4 15.4 14.0 21,0 15.8 10.15

Water 0.3 0.0 0.2 2.3 0.6 0.0 0 1 0.2 0.1. Shore Hardness A) 01 0s 71 04 0e 00 02 02 05 SP1 Volatile loss. percent in 24 hr 70 0.4 0.4 1.3 9.8 0.6 0.] 0.! 0.7 4 4 Heat Stability: Initial Color, percent BLR. S6 82 7t 81 QB 56 76 88 Mlmat 158 C. to BLR 217 300 240 00 252 ag 132 216 140 Sweat-out: two weeks None None None None None None Slight None None The data in this table demonstrates the compatibility g viscosity of 1625 cps. at C., a titration equivalent of the lactone-hydroxy ester adducts, their good to of 749.5 (theory 526.7), a saponification equivalent of excellent low temperature performance and heat stability, 170.4 (theory 175.6), an index of refraction at n /D resistance to oil and water extraction and to loss by of 1.4702 and a molecular weight of 820. evaporation. These desirable characteristics are par- 300 grams of the lactone-ricinoleic acid adduct thus ticularly surprising in the case of the castor oil adducts prepared were dissolved in 250 cc. of toluene and heated in view of the incompatibility of castor oil per se and for 42.5 hours at l65-l77 C., the water from the reacof acetylated castor oil. tion being removed by means of a decanter. The reaction In accordance with another embodiment of the invenmixture was stripped in a goose-neck still to 150 C. at tion one or more lactones are reacted with a high molec- 4 mm. and yielded 284 grams of a residue product having ular weight hydroxy carboxylic acid to form adducts an acidity of 0.350 cc. N base/g., a viscosity of 5300 cps. having one or more terminal hydroxy groups and one or at 25 C. and a molecular weight of 2060. more terminal carboxylic acid groups, the number of A mixture of one part by weight of the polyester thus such terminal groups corresponding to the number of obtained was mixed with two parts by weight of an 85% hydroxy and carboxylic acid groups in the initial hydroxy vinyl chloride-15% vinyl acetate copolymer VYHH carboxylic acid. These adducts may also be acylated resin cast from solution and dried. A clear, flexible film and esterified to improve their resistance to extraction was obtained indicating excellent compatibility of the when used as plasticizers in vinyl and other resins. polyester with the resin. Additional tests indicated that The conditions of reaction are generally similar to the polyester is also compatible with nitrocellulose. those described with reference to the reaction of lactones It is to be understood that many modifications will with a hydroxy ester. Inasmuch as the adducts have at readily occur to those skilled in the art upon reading this least one terminal hydroxy group and at least one ter- 5 description. All such modifications are intended to be minal carboxylic acid group, they are capable of selfincluded within the scope of the invention as defined in esterification upon further heating or, if desired, the the appended claims. terminal hydroxy group or groups may be acylated and I claim: 1 a the terminal carboxylic acid groups esterifiecl to form 1. An adduct of an epsilon-caprolactone having up to terminal acyl and ester groups, respectively. 5 three alkyl substituents and glyceryl ricinoleate.

The adducts obtained by reaction of a lactone with 2. An adduct of an epsilon-caprolactone having up to a hydroxy carboxylic acid may conveniently be reprethree alkyl substituents and lower alkyl ricinoleate. sented by the general formula 3. An adduct of an epsilon-caprolactone having up to three alkyl substituents and Z-ethylhexyl ricinoleate.

4. An adduct of an epsilon-caprolactone having up to R three alkyl substituents and a glycol diricinoleate.

\(CLzzh 5. An adduct of an epsilon-caprolactone having up to ll three alkyl substituents and 3-methyl-1,5-pentanediol di ricinoleate. in which is a residue of a high molecular weight 6. An adduct of an epsilon-caprolactone having up to hydroxy acid, Z is or alkoxy, z is one or more three alkyl substituents and glyceryl tr1-l2-hydroxy and the remaining symbols are as indicated previously, ,stearatethe L group in the 7. An adduct of an epsxlon-caprol actone havmg up to three alkyl subst tuents and tnbutyl citrate. i 8. An adduct of an epsilon-caprolactone having up to 0 three alkyl substituents and ricinoleic acid. group having the terminal hydroxy group linked to the Method which ccmprises reacting a lactone having carbonyl carbon and the terminal carbonyl group of from six to e g Carbon-atoms in the lactone ring and the lactone residue being linked either to Z or to the up to three alkyl substituents with a hydroxy group-conterminal oxy group of an adjacent lactone. residue. [5 taining compound of the group consisting of ricinoleic acid, hydroxy stearic acid, citric acid, and the lower alkyl esters, glycol esters and glycerides thereof.

10. Method as defined in claim 9 wherein the lactone is unsubstituted epsilon-caprolactone.

11. Method as defined in claim 9 wherein the lactone is a methyl epsilon-caprolactone.

12. Method as defined in claim 9 wherein the hydroxy group-containing compound is ricinoleic acid.

13. Method as defined in claim 9 wherein the hydroxy group-containing compound is glyceryl ricinoleate.

14. Method as defined in claim 9 wherein the hydroxy group-containing compound is a lower alkyl ricinoleate.

15. Method as defined in claim 9 wherein the hydroxy group-containing compound is a glycol ricinoleate.

16. Method as defined in claim 9 wherein the hydroxy group-containing compound is a lower alkyl ester of citric acid.

17. Method as defined in claim 9 wherein the hydroxy group-containing compound is glyceryl trihydroxy stearate.

18. Method as defined in claim 9 wherein the reaction product is acylated with a lower alkyl carboxylic acid anhydride.

19. An adduct of a lactone having from six to eight carbon atoms in the lactone ring and up to three alkyl substituents with a hydroxy group-containing compound of the group consisting of ricinoleic acid, hydroxy stearic acid, citric acid, and the lower alkyl esters, glycol esters and glycerides thereof.

20. An adduct of a lactone having from six to eight carbon atoms in the lactone ring and up to three alkyl substituents with a hydroxy group-containing compound of the group consisting of ricinoleic acid, hydroxy stearic acid, citric acid, and the lower alkyl esters, glycol esters and glycerides thereof acylated with a. lower alkyl carboXylic acid anhydride.

References Cited in the file of this patent UNITED STATES PATENTS Brandner et al. June 28, 1955 

9. A METHOD WHICH COMPRISES REACTING A LACTONE HAVING FROM SIX TO EIGHT CARBON ATOMS IN THE LACTONE RING AND UP TO THREE ALKYL SUBSTITUTENTS WITH A HYDROXY GROUP-CONTAINING COMPOUND OF THE GROUP CONSISTING OF RICINOLEIC ACID, HYDROXY STEARIC ACID, CITRIC ACID, AND THE LOWER ALKYL ESTERS, GLYCOL ESTERS AND GLYCERIDES THEREOF.
 19. AN ADDUCT OF A LACTONE HAVING FROM SIX TO EIGHT CARBON ATOMS IN THE LACTONE RING AND UP TO THREE ALKYL SUBSTITUENTS WITH A HYDROXY GROUP-CONTAINING COMPOUND OF THE GROUP CONSISTING OF RICINOLEIC ACID, HYDROXY STEARIC ACID, CITRIC ACID, AND THE LOWER ALKYL ESTERS, GLYCOL ESTERS AND GLYCERIDES THEREOF. 